Pick up an on-contract iPhone in the US and you’re looking to pay, minimum, $60 a month for service, and that’s without SMS and only 300MB data. If you wanted unlimited service, voice, SMS, and data included, you’ll be paying Sprint about $110 a month, which quickly starts adding up. If you don’t mind shelling-out a little more up front, though, Cricket will soon offer the iPhone on its prepaid plans, bundling everything together for just $55 a month.

Now, to be fair, Cricket’s “unlimited” data isn’t quite that, with throttling past the 2.3GB “fair use” threshold. Even with that in mind, it’s a heck of a deal compared to what you’d pay for equivalent service from some of the big iPhone carriers – Verizon with unlimited voice, SMS, and with 2GB of data is $120 a month, more than Sprint’s full-on unlimited plan.

What about those higher out-of-pocket costs, though? Cricket has the 16GB iPhone 4S for about $500, or you can go with the 8GB iPhone 4 for just $400. Take the time to do the math for what a year of service will cost on other carriers, and you’ll probably see those prices in a much different light.